Re: profiling connection overhead

Robert Haas <robertmhaas@gmail.com> wrote:
> Jeff Janes <jeff.janes@gmail.com> wrote:
 
>> Oracle's backend start up time seems to be way higher than PG's.
 
> Interesting.  How about MySQL and SQL Server?
 
My recollection of Sybase ASE is that establishing a connection
doesn't start a backend or even a thread.  It establishes a network
connection and associates network queues and a connection context
structure with it.  "Engine" threads with CPU affinity (and a few
miscellaneous "worker" threads, too, if I remember right) do all the
work in a queue-based fashion.
 
Last I worked with MS SQL Server it was based on the Sybase code and
therefore worked the same way.  I know they've made a lot of changes
in the last five years (including switching to MVCC and adding
snapshot isolation in addition to the already-existing serializable
isolation), so I don't know whether connection startup cost has
changed along the way.
 
-Kevin